Although the weather isn't yet dry enough to lay a patio, you can still get planning.

Spend time getting to know the space before you begin designing the area on graph paper, considering things such as sunny spots, slopes, sheltered places and those exposed to the elements.

Also think about the neighbours and issues of privacy.

With a clear idea of the layout you want, draw up a plan of the garden to show fixed features such as the patio, trees, shrubs, walls and water features.

Don't forget that grass, shingle, gravel, pebbles or bark can be used to break up large areas of paving and add interest.

Remember to include footways to storage sheds to avoid muddying up the garden in the wetter months and plan ahead for things you might want to add in at a later date too, such as built-in barbecues or ponds.

Also check there are no pipes, cables and so on, that need to be avoided.

The patio should be no higher than 150mm below the damp proof course at the house wall, otherwise your walls will get damp. To stop rainwater pooling on the patio, a gentle slope away from the house is needed, at a gradient of 1:40 in most circumstances. Larger patios also need a cross fall of 1:80.

Drive pegs into the ground to mark out the intended patio site, making sure their tops are at the height of the proposed finished level.

Build up a grid of pegs and wrap string between them, to indicate the gradient of the overall fall.

The amount of soil that needs to be dug away can be worked out by measuring down from the top of the pegs and allowing enough for the thickness of the slabs together with the various layers of the base.

The height of the string will help you with this process.

Slabs can be laid on a compacted 50mm bed of sand if the patio is for light use, whereas a 50mm semi-dry mix of sand and cement is more stable and better for most patios. For heavy use, you'll need a 75mm layer of compacted hardcore - broken brick and rubble - below the sand/cement mix to give a solid, stable base. It's best to hire a plate vibrator for this job.

To calculate the volume of hardcore needed, simply multiply the thickness required by the area of patio, then allow a little extra to account for compaction.

When the base is in place and properly firmed down, start laying the flagstones in one corner, applying five generous trowels of mortar for light patio use. Heavier use requires a continuous, 50mm thick bed of mortar instead of dabs, to give the slabs better support and help stop them cracking.

Once in place, take a club hammer and spirit level and tap the surface of the slab to level it down, using the string between pegs to help gauge the fall. It is likely there will be a gap of around 5-10mm where the slabs meet up, so wedge pieces of hardboard between them to keep the gaps even.

Work across the house wall first, then down one side before diagonally filling in the middle, leaving until the end any cutting that needs doing with a hired grinder or bolster chisel.

Trowel into the gaps fairly dry mortar mix to create a neat join, then brush off any excess before it dries.